Authorities have uncovered a massive narcotics mill in the Bronx — and seized $7.5 million in heroin and fentanyl, including some labeled “Death” and “Kill.”

Investigators found the haul during a court-authorized search of the illicit packaging plant in the Soundview neighborhood, according to a statement from the city’s Office of the Special Narcotics Prosecutor.

Equipment used to package the narcotics for street-level sale was found in a second bedroom — including nearly 16 tape dispensers, 300 rolls of tape, three scales, four strainers and 12 electric coffee grinders, according to Special Narcotics Prosecutor Bridget Brennan.

There were also three cases of glassine envelopes and more than 100 ink stamps used to brand them, officials said.

“Dexter,” “Super High,” “Kill Ducati” and “Heartless” were among the stamp names.